Method for preparing paper stocks



Jan. 4, 1966 H. BIDWELL 3,

METHOD FOR PREPARING PAPER STOCKS Filed May 17, 1961 3 Sheets-Sheet 1 F 3 IN VEN TOR. j #Mm/ IBM/WM Jan. 4, 1966 H. BIDWELL 3,227,606

METHOD FOR PREPARING PAPER STOCKS Filed May 17. 1961 3 Sheets-Sheet 2 INVENTOR. /7Zwara fi/awel/ Jan. 4, 1966 H. BIDWELL METHOD FOR PREPARING PAPER STOCKS 3 Sheets-Sheet 5 Filed May 17. 1961 INVENTOR. f/owaro/ fizz we By @[W-J-Mdj United States Patent 3,227,606 METHOD FOR PREPARING PAPER STOCKS Howard Bidwell, Granby, Mass., assiguor of one-half to Rachel Bidwell, Granby, Mass. Filed May 17, 1961, Ser. No. 118,756 1 Claim. (Cl. 162-4) This invention relates to methods and apparatus for preparing paper stocks for subsequent refining. More particularly it relates to methods and apparatus for the reduction of dry, raw, fibrous aggregate to a suitable condition for further processing and refining.

In general, this invention relates to apparatus comprising granular working surfaces contoured to manipulate paper stock to accomplish pulp processing and is exemplified by Patents Nos. 2,912,174, 2,936,128, 3,058,678, 3,116,028 and my copending applications, Serial No. 78,072, filed December 23, 1960, now abandoned; Serial No. 89,423, filed February 15, 1961; Serial No. 93,272, filed March 3, 1961.

The principal object of the invention is to effect the reduction of dry, raw, fibrous aggregate of all types, to a fiowable stock in such manner that the fibrous characteristics of the stock, whatever its nature, is rapidly transformed from a rigid, stifi, unyielding condition, to a tempered condition in which the fibers are characterized by their softness, pliability and toughness. Tempered fibers are more resistant to cutting and reduction of their length than dry fibers. Moreover, tempered fibrous materials can be readily separated into individual fibers and fibrillated, by water-home flow contact with and impingement against granular surfaces.

A further object is to achieve a fiber condition, for subsequent refining, superior to that obtainable by conventional preconditioning methods, and which is reached in less time and with less expenditure of power.

Another object of this invention is to provide means for the reduction of paper broke for return from the paper making machine to the stock preparation system.

Other and further objects and advantages are made apparent in the disclosure of the accompanying drawings and in the following specification and claims:

FIG. 1 is a cross sectional elevational view of one type of paper stock preconditioner embodying this invention;

FIG. 2 is a plan view, partly in section, of the apparatus shown in FIG. 1;

FIG. 3 is a section taken along line 33 of FIG. 2;

FIG. 4 is a cross sectional end view showing an alternative form of preconditioner embodying this invention;

FIG. 5 is a cross sectional side view of the apparatus shown in FIG. 4;

FIG. 6 is a plan view, partly in section, of the apparatus shown in FIG. 5;

FIG. 7 is a section taken along line 7-7 of FIG. 6;

FIG. 8 shows a cross section of an elevational view of one end of a paper broke reclaiming unit;

FIG. 9 shows a fragmentary side view of the same unit attached at the bottom center point; and

FIG. 10 is a diagrammatical showing reclaiming apparatus oriented in relation to the dry end of a paper making machine; and

FIGS. 11 and 12 are diagrammatical views showing the application of this invention for reclaiming paper web at the wet end of a paper making machine.

It has been found that superior reduction of a dry, raw, fibrous material can be obtained by moisturepenetrating or tempering a portion of the aggregate and continuously separating the so tempered or penetrated portion of the aggregate from the remainder.

In FIGS. 1-3, shown generally at 8, is one type of apparatus for preconditioning raw paper stock prior to introduction of the stock into apparatus for carrying out subsequent phases of the pulp preparation process, such as described in my copending application, Serial No. 93,272. The apparatus embodying the invention comprises a chamber or vessel 10 opening upwardly to permit the introduction of raw paper stock, such as shown at 12, in FIG. 1. The vessel includes an inlet opening 14 for fluid and an opening 16 for discharging water-borne stock. Disposed within the vessel are a plurality of granular-surfaced cylindrical rolls 18, 20, 22 and 24, mounted in side-by-side, spaced relation with their axes parallel. The rolls are formed of a porous, or moisturepervious, coarse, granular material of the type described in my above-referenced patents and applications. As shown, the rolls are mounted on tubular shafts 26 which are provided with a number of radially extending holes or perforations 28 to enable fluid to be forced through the porous granular material and discharged radially from the outer surfaces of the rolls. For ease of manufacture the rolls may be, and as shown are, composed of a number of sections.

As shown, the tubular shafts extends through openings in the walls of the vessel which may be sealed by seal rings 29. The shafts are supported by bearings 30 and may be rotated by any suitable means, not shown. The shafts 26 may be drivingly connected to the cylindrical rolls by any suitable means such as end plates 32 and bolts 34.

In the arrangement shown, the rolls are rotated in the same direction such as indicated by the arrows in FIG. 1 with their upper surface portions moving generally toward the inlet opening 14. The rolls are preferably rotated at relatively slow speeds so as to separate the tempered portions of the fibrous aggregate with minimum damage to the fibers, the speed of rotation of each roll being different than the speed of the adjacent rolls. In the illustrated embodiment, the roll 22 is rotated at a speed twice the speed of rotation of the roll 24, and the roll 20 is rotated at twice the speed of rotation of the roll 22. The major portion of the vapor-penetrated aggregate is thus carried toward the roll 18. The roll 18 is preferably rotated at a substantially lower rate than the other rolls and acts more or less as an anvil against which the major portion of the vapor-penetrated stock is carried and introduced into the fluid flowing into the vessel through opening 14.

The surfaces of the rolls are deeply scored or contoured to provide eflicient fiber separation and motivation with minimum damage or breakage of the individual fibers. In operation of the apparatus shown in FIGS. l3, the dry fibrous aggregate 12 is charged or introduced into the vessel through its top opening so that it comes to rest directly on the upper surfaces of the granularsurfaced rolls. Fluid, such as low-pressure steam, is introduced into the tubular shafts with sufficient pressure to be emitted radially from the surfaces of the rolls. The steam rapidly penetrates the fibers of the stock aggregate contiguous the roll surfaces. The steam tempers the fibers, in eliect, paving the way for more rapid saturation when the stock comes into contact with fluid introduced into the vessel through pipe connection 14. The tempered fibers of the stock are characterized by pliability, tensile strength and handleability superior to the dry fibers. Moreover, the tempered portions of the fibrous aggregate are readily separable, with minimum fiber damage, from the remainder of the aggregate composed of the dry or untempered fibers. Continuous rotation of granularsurfaced, vapor-emitting rolls acts to further separate the tempered fibers and transfer them into the fluid flowing below the rolls in such a state of wettability that they quickly become moisture-saturated.

Rotation of the granular-surfaced rolls 18, 20 and 22 turbulently advances the water-borne pulp toward the outlet opening 16 from which the pulp may be introduced into apparatus suitable for carrying out subsequent phases in the pulp-making process.

While the conditioner, shown and described in FIGS. 1-3, is highly effective for preconditioning fibrous materials of the type considered easy to pulp, in FIGS. 47 is shown an apparatus 40 preferable for use in preconditioning materials considered ditficult to pulp, such as hair seed fibers, which may be in sheet or bulk form, or in the form of woven fabrics.

The conditioner 40 comprises a vessel or chamber 42 supported by a base 44. The vessel has an open top for receiving pulp 46 which may be introduced into the vessel by means of a conveyor, such as shown at 48.

The conditioner comprises a pair of coarse, granularsurfaced rolls 50 and 52 disposed in spaced, side-by-side relation with their axes parallel and lying in a generally horizontal plane for supporting the aggregate on their upper surfaces. The rolls are of generally porous character as described above, and are mounted on tubular shafts 54 and 56. The shafts may be provided with openings or perforations for supplying fluids such as lowpressure steam, water, or a combination of both which may be introduced into the shafts through any suitable rotary joints, such as shown at 57. Due to the porous nature of the cylindrical rolls, the fluids will be discharged from the outer surfaces of the rolls. Means is provided for rotating the rolls 50 and 52 at different speeds and with their upper surfaces moving inwardly and downwardly for carrying the moisture-penetrated pulp downwardly toward a rotor 64 and for reducing the moisturepenetrated portions of the aggregate as it passes through the nip. The reducing action depends on the differential speeds of the rolls and their coarse surface texture and contouring. The rolls 50 and 52 comprise separate granular sections. Two of the granular sections tend to propel the aggregate in one direction, to the right as shown in FIG. 6, while the contours of the remaining sections tend to reverse this direction of movement of the aggregate. This opposing movement of the aggregate along the axes of the rolls and within the chamber 46, increases the effectiveness of the reduction of the aggregate. In the embodiment shown, the roll drive means comprises motors 58 and 59 drivingly engaged with the tubular shafts 54 and 56 respectively by worms 60 and pinions 62.

The rotor 64 is disposed below the rolls 50 and 52 with its axis parallel to the axes of the upper rolls and directly below the nip formed by the opposed surfaces of the upper rolls. The rotor has a coarse granular outer surface similar to the rolls 50 and 52 and is also porous in nature. The rotor is mounted on a tubular drive shaft 65 which may be perforated to supply or remove by suction fluid from the conditioning vessel through the porous rotor. In this way the amount of fluid in the vessel 42 may be effectively controlled to obtain stock having the desired characteristics. The shaft 65 may be driven by any suitable means, not shown, for rotating the shaft at a different speed and preferably faster than the upper rolls. The rotor 64 comprises a cylindrical portion and a frusto-conical portion 66 at its outer end.

The rotor 64 is spirally contoured throughout its length to impel the stock toward a discharge orifice 68. The rotor is mounted within a coarse granular-surfaced porous shell or stator member 70 disposed in the bottom of the conditioner, extending generally throughout the length of the cylindrical portion of the rotor. The inner surface of the stator is coaxial with and radially spaced from the outer surface of the rotor 64. The portion of the stator underlying the upper rolls is of generally semicylindrical configuration, while the remainder of the stator is cylindrical, entirely surrounding the rotor.

Drain openings 72 are provided in the bottom of the vessel 42 for discharge of surplus water which passes through the walls of the porous stator 70.

The conical end portion of the rotor 64 extends into a chamber 73 of conical cross section communicating with the orifice 68. As the fibrous mass is forced toward the conical end of the vessel by the contoured rotor 64, the fibrous mass is de-watered, that is, unabsorbed or surplus water is extracted from the mass. The de-watered fibers are forced through the orifice 68 into a chamber 76 in a dense, firm, compact mass or wad. Disposed within the chamber 76 is another granular-surfaced roll 7 8 disposed with its axis normal to the axis of the rotor 64. Means, such as motor 84, is provided for rotating the roll 78. The orifice 68 is of relatively small cross sectional size terminating adjacent the periphery of the roll 78 to insure engagement of the maximum number of fibers with the coarse surface of the roll. The chamber also includes an adjustable granular-surfaced shoe 80 extending through a portion of the periphery of the roll 78. The spacing between the opposed surfaces of the shoe 80 and the roll is adjustable by cam 81 for effective abrading action on the fibers. The chamber 76 is provided with an outlet 82 through which the preconditioned fibrous material may be supplied to subsequent apparatus employed in the pulping process.

Water may be injected into the chamber 76 through an inlet port 83 to maintain the rotor 78 in relatively cool and clean condition and aid in the discharge of the fibers in a flowable condition.

Operation of the apparatus shown in FIGS. 47 is commenced by introduction of dry, fibrous stock aggregate, through the top opening of the vessel. As shown in FIG. 4, this material is supported by the upper surfaces of the rolls 50 and 52. The stock supporting rolls are rotated in opposite directions such as indicated by arrows in FIG. 4. The fluid, such as low-pressure steam, discharged from the rolls continuously penetrates the fibers of the aggregate, contiguous with the surfaces of the rolls. Rotation of the coarse, granular-surfaced rolls gently separate the vapor-penetrated portions of the aggregate from the remainder of the aggregate and carries them downwardly toward the upper surface of the rotor 64. Rotation of the rotor acts to maintain the surfaces of the upper rolls in generally clean condition and causes further reduction of the fibrous aggregate. The surface contouring of the rotor advances the pulp toward the orifice 68.

The conical end 66 of the rotor 64 and the orifice 68 act to compress the moisture-ladden fibers extracting surplus or unabsorbed water and discharging it through the porous cylindrical stator and the ports 72. The rotor 64 forces the fibers in a dense compact mass through the orifice 68. The action of the coarse-surfaced rotor 78 on the dense wad of fibers effectively ruptures and removes the primary Wall portions of the fibers. Primary wall is the name applied to the tenacious outer surface of cellulosic fibers. Unless the primary wall is broken down or ruptured sufliciently to permit full utilization of fiber aifinity for moisture, extensive beating of the pulp is required. As mentioned above, the rotor 78 exerts an abrading action on the dense fibrous mass forced through the orifice 68 with the attainment of a high degree of fiber treatment such that the maximum number of fibers are subjected to rupture and at least partial removal of their primary wall. Fibers so treated are prone to rapid swelling and the formation of fibrels with a resultant increase in external fibrous surface area which enables rapid and effective fiber treatment in the following refining phase as well as high bonding ability.

While the conical end 66 of the rotor is shown as being granular surfaced, it may alternatively be of metallic construction on which spiral flutes are provided to effect discharge of the fibers through orifice 68. The inner wall of the conical chamber 73 may also be provided with spiral flutes which will cooperate in the transmission of the fiber mass through the orifice 68.

It has been found that very little power input is required to precondition the fibrous aggregate from its condition of maximum fiber afiinity, or resistance to separation, to a condition in which the fibers are readily separable.

The application of this invention is not confined to the preparation of raw stock but may also be suitably applied for reduction of either wet or dry paper broke such as may occur at either the wet or dry ends of a paper making machine. Utilization of a conditioner similar to the type described may be beneficially employed for reclamation of paper broke enabling the reclaimed stock to be returned to the main stock preparation system or directly into the paper machine chest in the form of high consistency stock.

In FIGS. 8, 9 and 10 is shown apparatus for reclaiming paper broke. In general the apparatus comprises a conditioner 39 and a unit 90 for further processing of the type disclosed in my Patent No. 3,116,028. The conditioner 89 is generally similar to the conditioner shown in FIG. 4, and like reference characters are used to indicate functionally similar components. The conditioner 89 comprises an upwardly open vessel in which are disposed granular surfaced porous rolls 50 and 52 and rotor 64 which are generally of the same construction as the like numbered members shown in FIG. 4. However, since this conditioner is utilized for handling a broken web of paper, the rolls and rotor may be considerably smaller in diameter than those described above. As shown in FIG. 9, the rolls and rotor sections 91 are contoured to move the web axially toward the center of the rolls for introduction into the unit 90 to reduce the web stock to pulp and return the pulp to the machine chest or stock preparation system. As shown the conditioner is provided with sprays 100 for moistening webs of paper being processed by the unit.

The reclamation apparatus is adapted to handle a web of paper, such as shown at 96, should the web break in its travel through a paper making machine, a portion of which is shown in FIG. 10. The machine comprises a drier roll 94, a set of calender rolls 102 and a slitter 104. The slitter is used to sever the web longitudinally to provide a portion of its width as a leader for threading the web into the calender. The slitter is controlled to move transversely of the web gradually increasing the width of the leader until the webs entire width is being received by the calender.

Means is prow'ded for guiding the web into the conditioner 89 and for automatically starting the conditioner in response to breakage of the web. As shown in FIG. 10, spaced opposed members 106 and 108 are provided for guiding the web into the conditioner 89, through an opening 109 in the floor which supports the paper machine. A roll 110 is normally biased by any suitable means such as spring 110 toward a position closing a switch 111. With the web properly tensioned about the roll the switch 111 is kept open. However, if the web should break, the roll 110 would be moved sufiiciently by spring 110 to cause the switch 111 to be closed, thereby actuating the conditioner 89 including the sprays and roll members and the defibering unit 90, thereby eliminating any possibility of broke accumulation.

In FIGS. 11 and 12 the working side of a press doctor is shown generally at 114. A chute 116 is provided for receiving wet broke which collects in doctor bar 118 when the Web 96 breaks. The chute introduces the broke into reclaiming apparatus as shown and described above. Means may be provided for collecting the broke from the doctor bar and introducing it into the chute 116. As shown the collecting means comprises an endless belt 118 driven by a motor 119 in a direction so that its upper surface carries the broke toward the chute 116.

Within the limitation that all opposed working surfaces be sufiiciently spaced from each other to avoid cutting of the fibers, the relative position and spacing of the rolls to each other and of the rolls to the stators may be varied, to control the rate or volume of flow of the stock in conformity with the nature of the aggregate, its state of fiber separation, its initial or acquired water content, as attainment of the above disclosed objective teaching may suggest or require.

What is claimed is:

Method of conditioning fibrous stock which comprises moisturizing dry stock aggregate, continuously separating the moistened fibers from the remainder of the aggregate by means of rotating granular-surfaced rotors, thereafter compacting the separated fibers into a dense mass and abrading the mass by bringing it into contact with a rotating abrading surface to break down the primary outer wall of said fibers.

References Cited by the Examiner UNITED STATES PATENTS 804,313 11/ 1905 Handford 162-236 2,008,892 7/ 1935 Asplund 162--17 2,388,592 11/1945 Asplund 16223 2,454,532 11/1948 Walter 16223 2,523,642 9/1950 Becker 241235 2,565,420 8/1951 Ayers 24115 2,641,164 6/1953 Hill 162-26 2,667,106 1/1954 Hyman 162l55 2,717,195 9/1955 Armstrong 241 -18 2,855,829 10/ 1958 Allemann 162-255 2,879,952 3/ 1959 Pollitz 241-235 2,893,909 7/1959 Shouvlin 162236 2,917,245 12/1959 Polleys 241-15 2,936,128 5/1960 Bidwell 241157 DONALL H. SYLVESTER, Primary Examiner.

RICHARD D. NEVINS, MORRIS O. WOLK, Examiners. 

